There's a Battlefield: Bad Company 2 interview on PC Games Hardware chatting with Anders Gyllenberg of DICE, discussing technical details about the Frostbite engine and support for DirectX 11 features. Along the way a gameplay question gets jammed in there, as a question about DirectX 9 oddly asks about the missing prone feature, receiving this response: "Regarding prone that is a design decision which we won’t change in the full game."

Yeah, it's a fun experience... I was all for the prone & lean though. There's a pile of wooden posts at the first defense zone that's not high enough to protect your head while crouched, perfect for an enemy sniper to pop your melon.